Machine-to-machine (M2M) communication, also referred to as machine-type communication (MTC), is the communication of data between machines with little or no human interaction. MTC devices, such as smart meters, are typically designed to send small amounts of data with varying periodicity. The data transmissions are typically delay tolerant and can in many cases be sent without acknowledgement at the radio link level. If an expected data transmission is not received, an MTC application can request a peer MTC application to transmit the missing data. It is expected that, in the near future, the number of MTC devices in use will far exceed the number of devices for human use.
The signaling protocols in use by most networks were designed primarily for human-generated traffic. Using the same signaling protocols for MTC devices can lead to inefficient radio resource utilization. The amount of signaling required to set-up or terminate a communication session is one area of concern. Because an MTC device will usually send only a small amount of data, the signaling overhead for a given amount of MTC traffic (i.e., user plane) will be higher than the signaling overhead for a similar amount of human-generated traffic.
Another area of concern is the potential for congestion and/or system overload. If a large number of MTC devices attempt to access the network simultaneously, the system may become congested, which could negatively impact the quality of service (QoS) experienced by higher priority human-generated traffic. Also, a substantially reduced volume of MTC devices will be able to successfully access the network during the period of congestion.
It would be beneficial to reduce the amount of signaling associated with SDTs so that the degree to which a network needs to restrict MTC devices from attempting network access (if the network is so capable) can be lessened during periods of congestion, and so that the number of SDTs that can be completed on a given packet channel resource during any given time interval can be increased (i.e., improved packet channel utilization can be realized).
Therefore, there is a need for signaling protocol enhancements that reduce signaling overhead for MTC devices and thereby minimize the impact of these devices on human-generated traffic and maximize the number of successful accesses experienced by MTC devices during periods of congestion.